JP6757944B2 - Engine exhaust silencer - Google Patents

Description

The present invention relates to an exhaust silencer mounted on a vehicle equipped with an engine.

Vehicles such as automobiles are equipped with an exhaust silencer (muffler) to reduce engine exhaust noise. Generally, the exhaust muffler includes a muffler main body that forms a muffling space (expansion chamber), and an exhaust pipe that constitutes an exhaust path through which the exhaust passes in the muffling space. The exhaust pipe includes an exhaust introduction pipe that introduces engine exhaust into the muffling space and an exhaust outlet pipe that discharges the exhaust from the muffling space to the outside.

The exhaust noise input from the exhaust outlet of the exhaust introduction pipe into the muffler body is not transmitted to the exhaust inlet of the exhaust outlet pipe only along the flow of the exhaust, but is transmitted in all directions from the exhaust outlet of the exhaust introduction pipe. It is transmitted to the entrance of the exhaust outlet pipe. Therefore, in order to reduce the exhaust noise emitted from the exhaust outlet pipe, it is desirable to keep the exhaust outlet of the exhaust introduction pipe and the exhaust inlet of the exhaust outlet pipe as far apart as possible. When the exhaust outlet and the exhaust inlet are separated from each other, a problem is to secure a smooth flow of the exhaust flow in the silencer main body. Patent Document 1 discloses a muffler device that diffuses exhaust gas into a muffler main body by arranging a bell-shaped end member so as to face the exhaust outlet.

Japanese Unexamined Patent Publication No. 62-237039

In general vehicles such as automobiles, the exhaust silencer is usually placed under the rear floor of the vehicle. Therefore, there is almost no space in the front-rear direction of the vehicle, and the silencer body has to have a shape elongated in the vehicle width direction. In this case, the arrangement in which the exhaust introduction pipe is inserted into the muffler space so that the exhaust outlet approaches the rear wall of the muffler main body is an arrangement in which the muffler space in the muffler main body can be effectively used. In such an arrangement, the exhaust introduced from the exhaust outlet is blown to the rear wall, but the exhaust may not be smoothly guided to the exhaust inlet of the exhaust outlet pipe as it is.

An object of the present invention is to ensure a distance between an exhaust outlet of an exhaust introduction pipe and an exhaust inlet of an exhaust lead-out pipe in an exhaust muffler having a muffler main body long in the vehicle width direction, from the exhaust outlet to the exhaust outlet. The purpose of the present invention is to provide an exhaust silencer for an engine that can smoothly guide exhaust gas to an exhaust inlet.

The engine exhaust muffling device according to one aspect of the present invention is a vehicle engine exhaust muffling device, which includes a front wall and a rear wall arranged in the front-rear direction of the vehicle, a pair of side walls arranged in the vehicle width direction, and a vehicle vertical direction. A muffler main body, which is partitioned by an upper wall and a lower wall arranged in a row and has a muffling space long in the vehicle width direction, and an exhaust introduction pipe having an exhaust outlet and introducing the exhaust of the engine into the muffling space, respectively. A first exhaust lead-out pipe and a second exhaust lead-out pipe having an exhaust inlet and discharging exhaust gas from the muffling space to the outside, and an exhaust guide portion for guiding exhaust gas in a predetermined direction in the muffling space are provided. The exhaust introduction pipe penetrates the front wall near the center in the vehicle width direction, is arranged in the muffling space so that the exhaust outlet approaches the rear wall, and the first exhaust outlet pipe penetrates one of the side walls. The second exhaust outlet pipe penetrates the other side wall, and each exhaust inlet is in the vicinity of the front wall, and one end side and the other end of the front wall in the vehicle width direction. The exhaust guide portion is arranged at a position facing the exhaust outlet, and is provided with a guide surface for guiding the exhaust from the exhaust outlet toward the rear wall toward both sides in the vehicle width direction.

According to this exhaust muffler, the exhaust outlet of the exhaust introduction pipe is arranged so as to approach the rear wall of the muffler main body, while the exhaust inlet of the exhaust outlet pipe is arranged near the front wall. As a result, the exhaust outlet and the exhaust inlet can be separated from each other in the muffling space, and it is possible to make it difficult to transmit the exhaust noise of the exhaust introduction pipe to the exhaust outlet pipe. In addition, the exhaust discharged from the exhaust outlet of the exhaust introduction pipe is not simply sprayed on the rear wall of the silencer body, but is exclusively in the vehicle width direction, which is the longitudinal direction of the silencer body (silencer space) by the exhaust guide portion. You will be actively guided toward both sides. Since the exhaust inlets of the first and second exhaust outlet pipes are arranged on both sides of the front wall in the vehicle width direction, the exhaust can smoothly head toward the exhaust inlet. Therefore, it is possible to suppress the generation of exhaust resistance and airflow noise.

In the exhaust muffling device, the exhaust guide portion is arranged so as to face the central portion in the vehicle width direction of the exhaust outlet, includes a tip portion extending in the vertical direction, and the guide surface has the tip portion at the foremost portion. The structure can be such that the vehicle extends from the tip portion toward the rear side of the vehicle on both sides in the vehicle width direction.

According to this exhaust silencer, the exhaust gas discharged from the exhaust outlet first blows onto the tip of the exhaust guide, and both guide surfaces extending rearward from the tip naturally naturally both sides in the vehicle width direction, that is, the direction of the side wall. Will go to.

In the exhaust muffler, the exhaust guide portion is formed of a plate-shaped member separate from the muffler main body, and the upper end side of the exhaust guide portion is on the upper wall of the muffler main body and the lower wall is on the lower wall. It is desirable that the lower end side of the exhaust guide portion is attached to each.

According to this exhaust muffler, since the exhaust guide portion is made of a plate-shaped member separate from the muffler main body, the degree of freedom in the shape and the degree of freedom in the arrangement of the exhaust guide portion can be increased. Further, since the upper end side and the lower end side of the exhaust guide portion are attached to the upper wall and the lower wall of the muffler main body, respectively, the rigidity of the muffler main body can be increased as compared with the case of attaching to the rear wall, for example.

In this case, it is desirable that the silencer body has a streamlined shape on the rear side of the vehicle in a cross-sectional view in the front-rear direction of the vehicle in the central portion in the vehicle width direction.

According to this exhaust muffling device, by adopting the streamlined shape, the ridgeline portion where the planes intersect with each other is not exposed, and the appearance from the rear of the vehicle can be improved. Further, when the rear side of the vehicle is streamlined, it becomes difficult to attach the exhaust guide portion to the rear wall of the muffler main body. However, since the exhaust guide portion is attached to the upper wall and the lower wall of the silencer main body, simple attachment can be realized.

In the exhaust silencer, the exhaust guide portion includes an upper flange portion extending forward from the upper end edge of the guide surface and a lower flange portion extending forward from the lower end edge of the guide surface, and the upper flange portion It is desirable that the lower flange portion is attached to the upper wall of the silencer body and the lower flange portion is attached to the lower wall of the silencer body.

According to this exhaust silencer, the upper and lower flanges are used to attach the upper and lower ends of the exhaust guide to the upper and lower walls of the silencer body by means such as spot welding or plug welding. On the other hand, it can be easily fixed.

In the exhaust silencer, the exhaust guide portion extends downward from the front end edge of the upper flange portion and partially covers the front of the guide surface, or upward from the front end edge of the lower flange portion. It is desirable to have either or both of the lower control pieces that extend and partially cover the front of the guide surface.

According to this exhaust muffling device, the flow of exhaust gas that tends to separate from the guide surface to the front side can be regulated by the upper regulation piece or the lower regulation piece. Therefore, the exhaust guide portion can more satisfactorily guide the exhaust toward both sides in the vehicle width direction.

In the exhaust silencer, the lower wall is provided with a bead extending in the front-rear direction of the vehicle, and the lower flange portion is attached to the lower wall via a mounting plate extending in the vehicle width direction across the bead. Is desirable.

According to this exhaust silencer, a bead is provided on the lower wall of the silencer body, so that the rigidity of the silencer body can be increased. On the other hand, due to the formation of the bead, securing the seating surface of the lower flange portion becomes a problem. However, by providing the mounting plate that straddles the bead, the lower flange portion can be reliably and easily mounted on the lower wall.

In the exhaust silencer, it is desirable that the corners of the rear wall of the silencer body and the pair of side walls have a round shape.

According to this exhaust silencer, the exhaust that is guided by the exhaust guide portion and flows along the rear wall can be guided toward the front wall where the exhaust outlet is arranged in the vicinity by the round shape.

In the exhaust silencer, the first and second exhaust outlet pipes are a first straight pipe arranged so as to be adjacent to the front wall and a first straight pipe arranged substantially parallel to the first straight pipe, respectively. A two straight pipe and a curved pipe curved in a U shape are included, and one end of the first straight pipe and one end of the second straight pipe are connected to both ends of the curved pipe, respectively, and the first and second straight pipes are connected. The exhaust inlet of the exhaust outlet pipe is the other end of the first straight pipe, and is arranged so as to face the side wall, and the other end side of the second straight pipe penetrates the side wall. desirable.

According to this exhaust silencer, since the first and second exhaust outlet pipes include the curved pipe and the first and second straight pipes, the length of the first and second exhaust outlet pipes in the sound deadening space is lengthened. Can be done. As a result, the degree of reduction of exhaust noise in the first and second exhaust outlet pipes themselves can be increased.

In the exhaust silencer, it is desirable to further include a set plate for supporting the curved pipe by the upper wall and the lower wall of the silencer body.

According to this exhaust silencer, the set plate can increase the support rigidity of the first and second exhaust outlet pipes, and also increase the rigidity of the silencer body itself. Further, it is possible to prevent the exhaust guided to the front wall side from returning to the exhaust outlet of the exhaust introduction pipe by arranging the set plate.

According to the present invention, in an exhaust silencer having a silencer body that is long in the vehicle width direction, while ensuring a distance between the exhaust outlet of the exhaust introduction pipe and the exhaust inlet of the first and second exhaust outlet pipes, Exhaust from the exhaust outlet to the exhaust inlet can be smoothly guided. Therefore, it is possible to provide an engine exhaust muffling device capable of suppressing the generation of exhaust resistance and airflow noise.

FIG. 1 is a schematic view of an exhaust system of a vehicle to which an engine exhaust silencer according to the present invention is applied. FIG. 2 is a top view of the main silencer (exhaust silencer) according to the embodiment of the present invention in a state where the upper plate is removed. FIG. 3 is a perspective view of the main silencer. FIG. 4 is a sectional view taken along line IV-IV of FIG. FIG. 5 is a sectional view taken along line VV of FIG. FIG. 6 is a perspective view of the curved pipe. FIG. 7 is a perspective view of a mounting portion of the straightening vane (exhaust guide portion). FIG. 8 is a top view of the mounting portion of the straightening vane. FIG. 9 is a sectional view taken along line IX-IX of FIG. FIG. 10 is a perspective view of the straightening vane and its mounting plate. FIG. 11 is a front view of the straightening vane and the mounting plate. FIG. 12 is a left side view of the straightening vane and the mounting plate. FIG. 13 is a horizontal sectional view of the main silencer. FIG. 14 is a perspective view showing a straightening vane according to the modified embodiment. FIG. 15 is a cross-sectional view in the horizontal direction showing the main muffling device according to the modified embodiment.

[Vehicle exhaust system]
Hereinafter, the exhaust gas silencer for the engine according to the embodiment of the present invention will be described in detail with reference to the drawings. First, the exhaust system of the vehicle equipped with the exhaust muffling device will be schematically described with reference to FIG. In addition, in FIG. 1 and other drawings, front-back, left-right, and up-down direction indications are attached. These directions are relative to the vehicle. That is, the front-rear, left-right, and up-down directions used in the following description are the front-rear direction (vehicle front-rear direction), the left-right direction (vehicle width direction) shown in FIG. 1, and perpendicular to the paper surface of FIG. It matches the vertical direction, which is the direction. In addition, when referring to upstream and downstream, the flow direction of exhaust gas is used as a reference.

The vehicle is, for example, a four-wheeled vehicle, and includes an engine 1 and an exhaust device 10 constituting the exhaust system of the engine 1. The engine 1 is, for example, an in-line 4-cylinder gasoline engine with a turbocharger, and is installed horizontally in the engine compartment in front of the passenger compartment, that is, the cylinders are arranged so as to be arranged in the vehicle width direction. The exhaust device 10 is connected to the engine 1 and extends rearward along the lower surface of the vehicle.

The exhaust device 10 includes an exhaust manifold 11, a turbo supercharger 12, an exhaust pipeline 13, a first catalyst device 14, a second catalyst device 15, a pre-silencer 16, and a main muffler 2 (exhaust muffler). .. The exhaust manifold 11 has an exhaust passage having a branch end connected to the exhaust port of each cylinder head of the engine 1 on the upstream side and a collecting end on the downstream side for collecting the exhaust gas discharged from these exhaust ports in one flow path. Is provided inside. The turbocharger 12 is connected to the collecting end of the exhaust manifold 11, and uses the energy of the exhaust gas discharged from the engine 1 to supercharge the intake air of the engine 1.

The exhaust pipe line 13 is a pipe line serving as an exhaust passage, is connected to the downstream end of the turbocharger 12, and extends rearward. The first catalyst device 14, the second catalyst device 15, and the pre-silencer 16 are incorporated in the exhaust pipeline 13 in this order from the upstream side, and the main silencer 2 is connected to the end. The first and second catalyst devices 14 and 15 purify harmful components in the exhaust gas discharged from the engine 1, for example, a catalyst containing a NOx storage reduction catalyst that temporarily stores NOx in the exhaust gas and then reduces it. It is composed of a main body and a casing for accommodating the catalyst main body.

The pre-silencer 16 and the main silencer 2 are incorporated in the exhaust system of the engine 1 in order to reduce exhaust noise. Of these silencers 16 and 2, the pre-silencer 16 arranged on the upstream side has a function of mainly reducing high frequency components in the exhaust noise. As the pre-silence device 16, for example, a sound absorbing type sound deadening device can be adopted, and a porous inner tube through which exhaust passes, an outer tube covering the inner tube, and filling between the inner tube and the outer tube are filled. It is provided with a sound absorbing material such as glass wool. On the other hand, the main muffling device 2 has a function of mainly reducing low and medium frequency components in the exhaust noise. Hereinafter, the structure of the main silencer 2 will be described in detail.

[Overall structure of main silencer]
FIG. 2 is a top view of the main silencer 2 (with the upper plate 20A described later removed), FIG. 3 is a perspective view thereof, FIG. 4 is a sectional view taken along line IV-IV of FIG. 2, and FIG. 4 is FIG. FIG. 6 is a sectional view taken along line IV-IV. FIG. 5 is a sectional view taken along line VV of FIG. The main muffler 2 is arranged under the rear floor at the rear end of the vehicle, and includes a muffler main body 20, an exhaust introduction pipe 3, a first exhaust outlet pipe 4A, and a second exhaust outlet pipe 4B.

The silencer body 20 is a housing that forms a silencer space S (expansion chamber) into which the exhaust gas of the engine 1 is introduced. The silencer body 20 has a shape that is relatively short in the front-rear direction and relatively long in the left-right direction, that is, a rectangular parallelepiped shape that is long in the vehicle width direction, flat in the vertical direction, and rounded as a whole. .. As a result, the muffling space S in the muffler main body 20 is also a long and flat space in the vehicle width direction.

The silencer body 20 has a front wall 21 and a rear wall 22 arranged in the front-rear direction of the vehicle, and a right wall 23 and a left wall 24 (a pair of side walls) arranged in the left-right direction (vehicle width direction) as walls for partitioning the sound deadening space S. ), And an upper wall 25 and a lower wall 26 arranged in the vertical direction (vehicle height direction). The front wall 21 is a wall extending linearly in the left-right direction. The rear wall 22 is a wall that is curved so as to have a gentle convex shape toward the rear in a top view and extends in the left-right direction. The right wall 23 and the left wall 24 are short walls extending linearly in the front-rear direction, and connect the front wall 21 and the rear wall 22 on the right end side and the left end side, respectively. As shown in FIG. 5, the left wall 24 has a substantially semicircular curved shape in a cross-sectional view in the left-right direction (the same applies to the right wall 23). The upper wall 25 is a wall that seals the upper surface of the space surrounded by the side wall including the front wall 21, the rear wall 22, the right wall 23, and the left wall 24, and the lower wall 26 is a wall that seals the lower surface of the side wall. is there.

As shown in FIG. 4, the silencer main body 20 has a streamlined shape on the rear side of the vehicle in a cross-sectional view in the vehicle front-rear direction (IV-IV line cross section in FIG. 2) in the central portion in the vehicle width direction. That is, the rear wall 22 has a streamlined portion St whose rear portion gently curves backward toward the rear. By equipping the silencer body 20 with such a streamlined portion St, the ridgeline portion where the planes intersect with each other is not exposed, and the appearance from the rear of the vehicle can be improved.

Further, as shown in FIG. 2, the corners of the rear wall 22, the right wall 23, and the left wall 24 have a round shape. That is, in the top view, the silencer body 20 has a shape in which the corners where the rear wall 22 and the right wall 23 intersect and the corners where the rear wall 22 and the left wall 24 intersect are chamfered. The round part R of is provided. The inner peripheral surface of these round portions R has a roughly curved shape. The round portion R contributes to the formation of a smooth exhaust flow F in the muffling space S, as will be described later based on FIG.

The silencer body 20 is composed of a joint body of an upper plate 20A and a bottom plate 20B, which is a half-split housing divided in the vertical direction. The upper plate 20A is a half-split housing having a cavity bulging upward, and has an upper flange portion 201 on the outer periphery of the lower edge thereof. The bottom plate 20B is a half-split housing having a cavity bulging downward, and has a lower flange portion 202 on the outer periphery of the upper edge thereof.

The upper plate 20A forms the upper wall 25 and the substantially upper half of the side wall, and the bottom plate 20B forms the lower wall 26 and the substantially lower half of the side wall. The upper flange portion 201 and the lower flange portion 202 are vertically overlapped and joined to form an upper plate 20A and a bottom plate 20B, and a silencer main body 20 having a silencer space S is formed. The upper wall 25 of the upper plate 20A and the lower wall 26 of the bottom plate 20B include a plurality of beads 203 extending in the front-rear direction. The bead 203 is a groove-shaped portion that is convex toward the sound deadening space S, and is provided for the purpose of increasing the rigidity of the sound deadening device main body 20 and the like.

The exhaust introduction pipe 3, the first exhaust lead-out pipe 4A, and the second exhaust lead-out pipe 4B are exhaust pipes constituting an exhaust path through which the exhaust gas passes in the sound deadening space S. That is, it is a pipe arranged to flow exhaust gas along a desired path in a closed space called a muffling space S. The exhaust introduction pipe 3, the first exhaust outlet pipe 4A, and the second exhaust outlet pipe 4B are pipes separated from each other. The exhaust introduction pipe 3 has an exhaust outlet A that blows exhaust gas into the muffling space S. On the other hand, the first and second exhaust outlet pipes 4A and 4B each have a first exhaust inlet B1 and a second exhaust inlet B2 for taking in the exhaust gas in the muffling space S. The exhaust gas discharged from the exhaust outlet A enters the muffling space S and expands, and then is taken into the first and second exhaust ports B1 and B2, and is discharged to the outside from the first and second outlet openings C1 and C2, respectively. Will be done.

The exhaust introduction pipe 3 is a linear hollow circular pipe that introduces the exhaust gas of the engine 1 into the muffling space S. A relay pipe 31 is inserted into the upstream end 302 of the exhaust introduction pipe 3. The upstream end of the relay pipe 31 is connected to the downstream end of the exhaust pipe line 13. The downstream end 301 of the exhaust introduction pipe 3 is the above-mentioned exhaust outlet A. The exhaust outlet A faces the rear wall 22.

The exhaust introduction pipe 3 penetrates the front wall 21 near the center in the left-right direction (center position in the vehicle width direction), and is arranged in the muffling space S so that the exhaust outlet A approaches the rear wall 22. That is, as shown in FIGS. 2 and 3, the front wall 21 of the exhaust introduction pipe 3 is arranged so that the exhaust outlet A is located closer to the rear wall 22 than the center in the front-rear direction of the silencer body 20. It is inserted from the side toward the muffling space S. In the present embodiment, the rectifying plate 6 described later is arranged between the exhaust outlet A and the rear wall 22.

With reference to FIG. 4, the upstream end 302 of the exhaust introduction pipe 3 is formed by a pair of pipe receiving portions 204 and 205, which are recesses provided in the center in the left-right direction of the front wall 21 of the upper plate 20A and the bottom plate 20B, respectively. It is supported so that it is sandwiched from above and below. Further, the vicinity of the downstream end 301 of the exhaust introduction pipe 3 serving as the exhaust outlet A is supported by the support plate 32. The support plate 32 is a sheet metal member, and is a vertical plate 321 extending in the vertical direction, a support hole 322 drilled in the vertical plate 321 and an upper flange portion 323 and a lower flange provided at the upper end and the lower end of the vertical plate 321, respectively. A unit 324 is provided. The support hole 322 penetrates and supports the exhaust introduction pipe 3. The upper flange portion 323 is fixed to the upper wall 25, and the lower flange portion 324 is fixed to the lower wall 26.

The exhaust introduction pipe 3 is attached to the muffler main body 20 upward so that the exhaust outlet A faces slightly upward. This is because water (condensed water) in the exhaust gas condensed in the sound deadening space S may stay on the lower wall 26, and the accumulated water does not flow back to the exhaust introduction pipe 3 through the exhaust outlet A. Is.

The first exhaust lead-out pipe 4A and the second exhaust lead-out pipe 4B are pipes for discharging the exhaust gas from the muffling space to the outside. The first and second exhaust outlet pipes 4A and 4B have the same components and are arranged symmetrically in the muffling space S to the left and right of the exhaust introduction pipe 3. That is, the first exhaust lead-out pipe 4A is arranged on the right wall 23 side and the second exhaust lead-out pipe 4B is arranged on the left wall 24 side with the exhaust introduction pipe 3 interposed therebetween. Further, the downstream end of the first exhaust outlet pipe 4A penetrates the right wall 23, and the downstream end of the second exhaust outlet pipe 4B penetrates the left wall 24.

The first and second exhaust outlet pipes 4A and 4B each include a first straight pipe 41, a second straight pipe 42, and a curved pipe 43. The curved pipe 43 is a U-shaped curved pipe. The first straight pipe 41 and the second straight pipe 42 extend parallel to each other in the left-right direction from both ends of the curved pipe 43. That is, one end of the first straight pipe 41 and one end of the second straight pipe 42 are connected to both ends of the curved pipe 43, respectively. The first and second straight pipes 41 and 42 may be arranged substantially in parallel, even if they are not arranged completely in parallel.

In the exhaust flow F of the first and second exhaust outlet pipes 4A and 4B, the first straight pipe 41 is an exhaust pipe arranged on the upstream side of the second straight pipe 42. The first straight pipe 41 is arranged so as to be adjacent to the front wall 21 extending linearly. That is, the distance between the front side portion of the first straight pipe 41 and the front wall 21 in the front-rear direction is narrow. On the other hand, the second straight pipe 42 is arranged at a substantially central position in the front-rear direction of the muffling space S, which is separated from the front wall 21 and also separated from the rear wall 22. The height positions of the first straight pipe 41 and the second straight pipe 42 in the vertical direction are substantially the same. The curved pipe 43 connects such first and second straight pipes 41 and 42 to each other.

FIG. 5 shows a cross section of the first straight pipe 41 of the second exhaust outlet pipe 4B in the left-right direction. The first straight pipe 41 is a pipe having a circular cross section extending linearly in the left-right direction, and includes an upstream end 411 (the other end) and a downstream end 412 (one end). The upstream end 411 is a pipe end portion having an opening that serves as the above-mentioned second exhaust inlet B2 (in the case of the first straight pipe 41 of the first exhaust outlet pipe 4A, the first exhaust inlet B1). The upstream end 411 is processed to increase the inner diameter in a bell mouth shape in order to smoothly take in the exhaust gas to the second exhaust inlet B2. The downstream end 412 is a pipe end portion inserted into the upstream end 431 of the curved pipe 43.

As described above, the exhaust outlet A is arranged at a position near the rear wall 22 (in the present embodiment, a position near the straightening vane 6 substantially corresponding to the rear wall 22), whereas the first and second exhaust outlets A are arranged. The exhaust ports B1 and B2 are arranged near the front wall 21 because the first straight pipe 41 is adjacent to the front wall 21. Further, the exhaust outlet A is arranged at the center position in the left-right direction, while the first and second exhaust ports B1 and B2 are arranged on the right end side and the left end side of the front wall 21, respectively. Specifically, the first exhaust inlet B1 faces the right wall 23 near the front wall 21, the second exhaust inlet B2 faces the left wall 24 near the front wall 21, and is close to the right wall 23 and the left wall 24, respectively. It is placed in position. By keeping the exhaust outlet A and the first and second exhaust ports B1 and B2 away from each other in this way, the exhaust noise of the exhaust introduction pipe 3 is hard to be transmitted to the first and second exhaust outlet pipes 4A and 4B. There is.

The second straight pipe 42 is a pipe having a circular cross section extending linearly in the left-right direction, and has a longer left-right width than the first straight pipe 41. The upstream end (one end) of the second straight pipe 42 is inserted into the downstream end 432 (FIG. 6) of the curved pipe 43. The downstream end (the other end) of the second straight pipe 42 of the first exhaust lead-out pipe 4A penetrates the right wall 23. A first tail pipe 44A is connected to the penetrating downstream end. Further, the downstream end of the second straight pipe 42 of the second exhaust lead-out pipe 4B penetrates the left wall 24. A second tail pipe 44B is connected to the penetrating downstream end. The downstream end of the first tail pipe 44A is the first outlet opening C1, and the downstream end of the second tail pipe 44B is the second outlet opening C2. Exhaust gas is discharged to the outside from these first and second outlet openings C1 and C2.

FIG. 6 is a perspective view of the curved pipe 43. With reference to FIGS. 5 and 6, the curved pipe 43 is a pipe having a substantially circular cross section and forming an exhaust path curved in a U shape. As described above, the curved pipe 43 includes an upstream end 431 to which the first straight pipe 41 is connected and a downstream end 432 to which the second straight pipe 42 is connected. The curved pipe 43 is composed of a joint body of a first half-split pipe 43A and a second half-split pipe 43B, which are half-split pipes divided in the vertical direction. The first half-cracked pipe 43A and the second half-cracked pipe 43B are joined to each other by the outer peripheral flange portion 433 and the inner peripheral flange portion 434. The outer peripheral flange portion 433 extends outward from the outer curved portion L1 of the curved pipe 43 curved in a U shape. On the other hand, the inner peripheral flange portion 434 extends inward from the inner curved portion L2 so as to fill the U-shaped space defined by the inner curved portion L2 of the curved pipe 43.

The first half-cracked pipe 43A has a semicircular cross section that bulges upward and has a U-shaped cavity when viewed from the bottom, and the upper flange portion 433A forming the upper side of the outer peripheral flange portion 433 is placed on the outer peripheral side and inside. The upper flange portion 434A forming the upper side of the peripheral flange portion 434 is provided on the inner peripheral side, respectively. The second half-cracked pipe 43B has a semicircular cross section that bulges downward, has a U-shaped cavity when viewed from above, and has a lower flange portion 433B that forms the lower side of the outer peripheral flange portion 433 on the outer peripheral side. , The lower flange portion 434B forming the lower side of the inner peripheral flange portion 434 is provided on the inner peripheral side, respectively. The upper flange portion 433A and the lower flange portion 433B, and the upper flange portion 434A and the lower flange portion 434B are vertically overlapped and joined to form the curved pipe 43.

The curved pipe 43 is provided with a non-flange portion 435 at the upstream end 431 and the downstream end 432, respectively. The non-flange portion 435 is a cylindrical portion of the curved pipe 43 in which the outer peripheral flange portion 433 and the inner peripheral flange portion 434 do not exist. The non-flange portion 435 has a slit SL having a wall thickness of the outer peripheral flange portion 433 and the inner peripheral flange portion 434 and an opening width corresponding to the bending allowance thereof. As shown in FIG. 5, the downstream end 412 of the first straight pipe 41 is inserted into the non-flange portion 435. Although not shown, the upstream end of the second straight pipe 42 is also inserted into the non-flange portion 435 on the downstream end 432 side. The downstream end 412 of the first straight pipe 41 is inserted into the curved pipe 43 to a position where it exceeds the non-flange portion 435 and reaches the outer peripheral flange portion 433. The same applies to the upstream end of the second straight pipe 42. As a result, the air leakage passage from the slit SL is blocked to prevent the generation of airflow noise.

As shown in FIGS. 3 and 5, the curved pipe 43 is supported by the silencer body 20 by the set plate 27. The set plate 27 is a flat plate member extending in the vertical direction, and has an upper flange portion 271 on the upper end side, a lower flange portion 272 on the lower end side, and two burring portions 273 in the center. The non-flange portion 435 of the upstream end 431 and the downstream end 432 of the curved pipe 43 is densely inserted into each burring portion 273. That is, the burring portion 273 supports the non-flange portion 435 into which one ends of the first and second straight pipes 41 and 42 are inserted.

The upper flange portion 271 is joined to the upper wall 25, and the lower flange portion 272 is joined to the lower wall 26. The upper wall 25 is provided with a welded hole (not shown), and the upper flange portion 271 is fixed to the upper wall 25 by plug welding. The lower flange portion 272 is fixed to the lower wall 26 by spot welding. By forming the non-flange portion 435 in this way, the curved pipe 43 is attached to the upper wall 25 and the lower portion of the set plate 27 having a simple support structure of the curved pipe 43, that is, a burring portion 273 having a simple round hole. A structure supported by the wall 26 can be realized, and the first and second straight pipes 41 and 42 can also be supported by the set plate 27.

The main silencer 2 includes a first silencer 51 applied to the first straight pipe 41, a second silencer 52 applied to the second straight pipe 42, and a curved silencer 53 applied to the curved pipe 43. To be equipped. These sound deadening portions 51 to 53 include a large number of small holes drilled in each pipe wall, a sound absorbing material that covers the outer periphery of the pipe wall portion having these small holes, and a sound absorbing material cover that covers the periphery of the sound absorbing material. Consists of. When airflow noise (exhaust noise) is generated in the exhaust passing through the first and second exhaust outlet pipes 4A and 4B, the airflow noise is released to the outside of the pipe through the small holes and is absorbed by the sound absorbing material. The sound absorbing material is, for example, glass wool.

The first muffling unit 51 is attached so as to cover a part of the circumferential direction of the first straight pipe 41 in a predetermined region in the pipe axial direction. Specifically, the first muffling portion 51 is provided only on the pipe wall portion (rear side portion) substantially facing the second straight pipe 42 in the entire circumference of the first straight pipe 41. That is, a large number of small holes are perforated in the facing pipe wall portion, the sound absorbing material is arranged on the outer periphery of the pipe wall portion having the small holes, and the sound absorbing material cover is in a first straight line so as to cover the sound absorbing material. It is attached to the outer peripheral surface of the pipe 41. As described above, such a partial arrangement is such that the distance between the front side portion of the first straight pipe 41 and the front wall 21 in the front-rear direction is narrow, and there is a space for arranging the sound absorbing material and the sound absorbing material cover. This is because it cannot be secured.

The second muffling unit 52 is attached so as to cover the entire circumference of the second straight pipe 42 in a predetermined region in the pipe axial direction. Specifically, in the predetermined region, the second muffling unit 52 is perforated with a large number of small holes over the entire circumference of the pipe wall of the second straight pipe 42, and the entire circumference of the pipe wall having the small holes is formed. The sound absorbing material is arranged so as to cover the sound absorbing material, and a tubular sound absorbing material cover capable of covering the sound absorbing material is attached to the outer peripheral surface of the second straight pipe 42. In order to increase the rigidity, the sound absorbing material covers of the first sound deadening unit 51 and the second sound deadening unit 52 are connected by a connecting member 54.

As shown in FIGS. 5 and 6, the curved sound deadening portion 53 includes a large number of small holes 43H perforated near the bulging apex of the first half-cracked pipe 43A and the second half-cracked pipe 43B, and the small holes 43H. It includes a sound absorbing material 7 that covers the outer peripheral surfaces of the first and second half-cracked pipes 43A and 43B, and an upper cover 53A and a lower cover 53B (sound absorbing material cover) that cover the sound absorbing materials 7, respectively.

The upper cover 53A covers the sound absorbing material 7 on the outer circumference of the first half-cracked pipe 43A, and the lower cover 53B covers the sound absorbing material 7 on the outer periphery of the second half-cracked pipe 43B. The upper cover 53A and the lower cover 53B each have a partial flange 531 on the outer curved portion L1 side of the curved pipe 43 and an auxiliary portion 532 on the inner curved portion L2 side. The partial flange 531 is a flange portion having a shape that partially overlaps the upper and lower flange portions 433A and 433B, respectively.

The upper flange portion 433A of the first half-cracked pipe 43A and the partial flange 531 of the upper cover 53A, and the lower flange portion 433B of the second half-cracked pipe 43B and the partial flange 531 of the lower cover 53B are spot welded in their respective overlapping portions. It is joined by welding. The upper and lower flange portions 433A and 433B are joined by spot welding at non-overlapping portions of the partial flanges 531. That is, in the outer peripheral flange portion 433, although the upper and lower flange portions 433A and 433B and the upper and lower two partial flanges 531 overlap each other, they are joined by spot welding of two layers. The attachment portion 532 is a curved portion in the vicinity of the upstream end 431 (downstream end 432) of the curved pipe 43, which is in contact with the outer peripheral surfaces of the bulging portions of the first and second half-cracked pipes 43A and 43B, respectively. Regarding the inner curved portion L2 side, the upper and lower covers 53A and 53B can be joined to the outer peripheral surface of the curved pipe 43 by, for example, wire welding.

The main muffling device 2 further includes a rectifying plate 6 (exhaust guide unit). The straightening vane 6 is installed at the center in the vehicle width direction and adjacent to the rear wall 22, and is arranged at a position facing the exhaust outlet A of the exhaust introduction pipe 3 also arranged at the center in the vehicle width direction. Has been done. The straightening vane 6 has a function of guiding the exhaust gas in a predetermined direction in the muffling space S. Specifically, the straightening vane 6 guides the exhaust from the exhaust outlet A toward the rear wall 22 in the left-right direction (both sides in the vehicle width direction). Hereinafter, the straightening vane 6 will be described in detail.

[Details of current plate]
FIG. 7 is a perspective view of a portion of the rectifying plate 6 attached to the silencer body 20, and FIG. 8 is a top view thereof. FIG. 9 is a sectional view taken along line IX-IX of FIG. 10 is a perspective view of the straightening vane 6 and its mounting plate 28, FIG. 11 is a front view thereof, and FIG. 12 is a left side view thereof. The rectifying plate 6 is made of a sheet metal member (plate-shaped member) that is separate from the silencer main body 20, and has a V-shaped bent shape in a roughly top view (FIG. 8). The straightening vane 6 includes a tip portion 61, a guide surface 62, an upper flange portion 63, and a lower flange portion 64. The straightening vane 6 is placed and fixed on the mounting plate 28.

The tip portion 61 is a portion extending in the vertical direction corresponding to the bent portion in the V-shaped bent shape. The tip portion 61 is arranged so as to face the central portion in the left-right direction of the exhaust outlet A. FIG. 8 shows the downstream end 301 of the exhaust introduction pipe 3 and the pipe shaft P of the exhaust introduction pipe 3. The position of the pipe shaft P corresponds to the position of the central portion of the exhaust outlet A in the left-right direction. The tip portion 61 has a curved shape that is convex forward when viewed from above. The curved protruding end (inflection point) of the tip portion 61 is arranged on an extension line of the pipe axis P extending in the front-rear direction.

The guide surface 62 is arranged at a position facing the exhaust outlet A, and has a function of guiding the exhaust from the exhaust outlet A toward the rear wall 22 toward both sides in the vehicle width direction. The guide surface 62 has a tip portion 61 as the frontmost portion, and extends from the tip portion 61 toward the rear side of the vehicle on both sides in the vehicle width direction. That is, the guide surface 62 includes a right guide surface 62R extending rearward to the right from the tip portion 61 and a left guide surface 62L extending rearward to the left from the tip portion 61. The right side region of the exhaust outlet A and a part of the right guide surface 62R, and the left side region of the exhaust outlet A and a part of the left guide surface 62L face each other. The right end edge 623, which is the rearmost end of the right guide surface 62R, and the left end edge 624, which is the rearmost end of the left guide surface 62L, are closest to the rear wall 22 in the straightening vane 6.

As shown in FIGS. 4 and 9, the tip portion 61 and the guide surface 62 have a vertical width substantially corresponding to the vertical width of the silencer main body 20, that is, a vertical width substantially extending from the upper wall 25 to the lower wall 26. Have. Further, the tip portion 61 and the guide surface 62 are at the upper ends in accordance with the fact that the exhaust introduction pipe 3 is attached to the muffler main body 20 so that the exhaust outlet A (downstream end 301) faces slightly upward. The side is tilted so as to be slightly downward (the IX-IX line in FIG. 4 is a perpendicular line). As a result, the downstream end 301, the pipe end edge, and the tip portion 61 are in a substantially parallel relationship.

The upper end side of the rectifying plate 6 is attached to the upper wall 25 of the silencer main body 20, and the lower end side of the rectifying plate 6 is attached to the lower wall 26 via the mounting plate 28. For this attachment, the straightening vane 6 includes a pair of upper flange portions 63 and a pair of lower flange portions 64. The pair of upper flange portions 63 extend forward from the upper end edges 621 of the right and left guide surfaces 62R and 62L, respectively. The pair of lower flange portions 64 extend forward from the lower end edges 622 of the right and left guide surfaces 62R and 62L, respectively. The upper flange portion 63 is provided with a lower portion 631 recessed downward in order to match the shape of the silencer body 20 with the bead 203 (see FIG. 9). The lower flange portion 64 is a flat plate without a step.

With reference to FIG. 9, the upper flange portion 63 is directly attached to the upper wall 25. The upper flange portion 63 is overlapped with the lower side of the upper wall 25. The lower portion 631 is fitted to the bead 203 that is convex downward. Welding holes 206 are drilled in the upper wall 25 in accordance with the arrangement positions of the pair of upper flange portions 63. The upper flange portion 63 is fixed to the upper wall 25 by plug welding using the welding hole 206.

On the other hand, the lower flange portion 64 is attached to the lower wall 26 via the mounting plate 28. The mounting plate 28 is a sheet metal member extending in the left-right direction, and includes a convex flat plate portion 281 and a joint portion 282 extending from the right end and the left end of the convex flat plate portion 281, respectively. The mounting plate 28 is formed by bending the strip-shaped sheet metal member so that the height position of the convex flat plate portion 281 is higher than that of the left and right joint portions 282. The convex flat plate portion 281 is a portion that serves as a seating surface of the straightening vane 6. The joint portion 282 is a portion that comes into contact with the lower wall 26.

In the present embodiment, a plurality of beads 203 extending in the front-rear direction are arranged on the lower wall 26 at a predetermined pitch. That is, the lower wall 26 has irregularities due to the formation of the bead 203. If plug welding is adopted on the lower wall 26 side as well as on the upper wall 25 side, the weld bead is exposed at the rear of the vehicle, so that the appearance from the rear of the vehicle is deteriorated. Therefore, it is preferable to use spot welding for fixing the straightening vane 6 on the lower wall 26 side. In this case, the presence of the unevenness is not desirable. Therefore, the mounting plate 28 is arranged so as to straddle the bead 203 to provide the seating surface of the straightening vane 6. In the example of FIG. 9, the convex flat plate portion 281 straddles two beads 203. The joint 282 is in contact with the lower wall 26 on the side of the bead 203. A pair of lower flange portions 64 of the straightening vane 6 are fixed to the mounting plate 28 by spot welding, and a joint portion 282 of the mounting plate 28 is fixed to the lower wall 26 by spot welding. Of course, if the lower wall 26 does not have irregularities such as beads 203, the lower flange portion 64 may be directly fixed to the lower wall 26 by spot welding.

FIG. 13 is a cross-sectional view of the main muffling device in the horizontal direction, showing an exhaust flow in the muffling space S. Here, the exhaust flow F1 from the exhaust outlet A of the exhaust introduction pipe 3 to the first exhaust inlet B1 of the first exhaust outlet pipe 4A and the exhaust from the exhaust outlet A to the second exhaust inlet B2 of the second exhaust outlet pipe 4B. The flow F2 is illustrated.

The exhaust introduction pipe 3 is arranged in the muffling space S so that the exhaust outlet A approaches the rear wall 22, and the rectifying plate 6 adjacent to the rear wall 22 is arranged at a position facing the exhaust outlet A. Therefore, the exhaust gas blown out from the exhaust outlet A first blows onto the straightening vane 6. The exhaust gas is divided into left and right by the tip portion 61 of the straightening vane 6, and is guided by the right guide surface 62R and the left guide surface 62L, respectively, whereby exhaust flows F1 and F2 are created.

The exhaust flow F1 formed by the right guide surface 62R goes to the right along the rear wall 22 and hits the right wall 23. On the other hand, the exhaust flow F2 formed by the left guide surface 62L heads to the left along the rear wall 22 and blows against the left wall 24. Here, the silencer main body 20 has round portions R at the corners where the rear wall 22 and the right wall 23 intersect, and at the corners where the rear wall 22 and the left wall 24 intersect, respectively. The inner surface of these round portions R serves as a guide, and the exhaust flows F1 and F2 head forward along the right wall 23 and the left wall 24. Then, the exhaust flows F1 and F2 enter the first and second exhaust ports B1 and B2. After that, the exhaust gas passes through the first and second exhaust outlet pipes 4A and 4B, and is discharged to the outside from the first and second outlet openings C1 and C2, respectively.

[Action effect, etc.]
According to the main muffling device 2 described above, the following actions and effects are obtained. In the main muffler 2, since the first and second exhaust outlet pipes 4A and 4B include the first and second straight pipes 41 and 42 and the curved pipe 43, respectively, the length of the exhaust pipe in the muffling space S is lengthened. be able to. As a result, the degree of reduction of exhaust noise in the first and second exhaust outlet pipes 4A and 4B themselves can be increased.

The exhaust outlet A of the exhaust introduction pipe 3 is arranged so as to approach the rear wall 22 of the muffler main body 20, while the first and second exhaust inlets B1 and B2 of the first and second exhaust outlet pipes 4A and 4B are in front. It is located near the wall 21 and is arranged on the right side and the left side, respectively. As a result, the exhaust outlet A and the first and second exhaust inlets B1 and B2 can be separated from each other in the muffling space S, and the exhaust noise of the exhaust introduction pipe 3 can be transferred to the first and second exhaust outlet pipes 4A and 4B. It can be difficult to communicate.

Further, the exhaust gas discharged from the exhaust outlet A of the exhaust introduction pipe 3 is not simply sprayed on the rear wall 22 of the silencer main body 20, but is exclusively provided by the guide surface 62 of the rectifying plate 6 (exhaust guide portion). The vehicle is actively guided toward both sides in the vehicle width direction, which is the longitudinal direction of the main body 20 (silence space S). Since the exhaust ports B1 and B2 of the first and second exhaust outlet pipes 4A and 4B are arranged on both sides of the front wall 21 in the vehicle width direction, the exhaust can be smoothly performed at the first and second exhaust ports B1. , You can head to B2. Therefore, it is possible to suppress the generation of exhaust resistance and airflow noise.

The straightening vane 6 includes a front end portion 61, and a right guide surface 62R and a left guide surface 62L extending from the tip portion 61 to the right rear and the left rear, respectively. Therefore, the exhaust gas discharged from the exhaust outlet A first blows onto the tip portion 61 of the straightening vane 6, and is naturally both sides in the vehicle width direction, that is, the right wall by the guide surfaces 62R and 62L extending rearward from the tip portion 61. It will be directed toward 23 and the left wall 24.

Further, since the rectifying plate 6 is made of a plate-shaped member separate from the muffler main body 20, the degree of freedom in the shape and the degree of freedom in arrangement of the rectifying plate 6 can be increased. Further, since the upper end side and the lower end side of the rectifying plate 6 are attached to the upper wall 25 and the lower wall 26 of the silencer body 20, respectively, the rigidity of the silencer body 20 is higher than that when the rectifying plate 6 is attached to the rear wall, for example. Can be enhanced.

As shown in FIG. 4, the silencer main body 20 is provided with a streamlined portion St at the rear portion of the rear wall 22 in a cross-sectional view in the vehicle front-rear direction in the central portion in the vehicle width direction. By providing the streamlined portion St, the ridgeline portion where the planes intersect with each other is not exposed, and the appearance from the rear of the vehicle can be improved. Further, when the rear portion of the silencer body 20 is streamlined, it becomes difficult to attach the rectifying plate 6 to the rear wall 22 of the silencer body 20. However, since the rectifying plate 6 is attached to the upper wall 25 and the lower wall 26 of the silencer main body 20, it is possible to realize a simple attachment of the rectifying plate 6. Further, since the straightening vane 6 includes the upper flange portion 63 and the lower flange portion 64, it can be easily fixed to the upper wall 25 and the lower wall 26 by, for example, plug welding or spot welding.

The lower flange portion 64 of the straightening vane 6 is attached to the lower wall 26 via a mounting plate 28 extending in the vehicle width direction across the bead 203 provided on the lower wall 26. By providing the lower wall 26 with the bead 203, the rigidity of the silencer main body 20 can be increased. On the other hand, due to the formation of the bead 203, securing the seating surface of the lower flange portion 64 becomes a problem. However, by providing the mounting plate 28 that straddles the bead 203, the lower flange portion 64 can be reliably and easily mounted on the lower wall 26.

Further, a set plate 27 for supporting the curved pipe 43 by the upper wall 25 and the lower wall 26 of the silencer main body 20 is provided. The set plate 27 can increase the support rigidity of the first and second exhaust outlet pipes 4A and 4B, and can also increase the rigidity of the silencer body 20 itself. Further, it is possible to prevent the exhaust gas guided to the front wall 21 side from returning to the exhaust outlet A of the exhaust introduction pipe 3 by the arrangement of the set plate 27. That is, since the set plate 27 is a flat plate extending in the vertical direction and is arranged so as to sandwich the exhaust introduction pipe 3, it can play a role of blocking the exhaust flow returning to the exhaust outlet A.

[Explanation of Modified Embodiment]
Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modified embodiments as shown below can be taken.

(1) FIG. 14 is a perspective view showing a straightening vane 6A according to the modified embodiment. The difference from the straightening vanes 6 shown in FIGS. 7 to 12 is that the pair of upper flange portions 63 has a pair of upper regulation pieces 65, and the pair of lower flange portions 64 have a pair of lower regulation pieces 66. It is a point provided. Since the other configurations are the same, the explanation is omitted here.

The pair of upper regulation pieces 65 extend downward from the front end edges of the pair of upper flange portions 63, respectively, and partially cover the front of the right guide surface 62R and the left guide surface 62L. The pair of lower regulation pieces 66 extend upward from the front end edges of the pair of lower flange portions 64, respectively, and partially cover the front of the right guide surface 62R and the left guide surface 62L. The upper and lower control pieces 65 and 66 can be formed by bending a predetermined width on the front end side of the upper and lower flange portions 63 and 64. Either the upper regulation piece 65 or the lower regulation piece 66 may be omitted.

When the exhaust gas blows onto the guide surface 62 of the straightening vane 6A, an exhaust flow that tends to return to the front side due to the bounce from the guide surface 62 may occur in a part of the exhaust gas. That is, most of the exhaust is guided in the left-right direction by the right and left guide surfaces 62R and 62L, but the rest of the exhaust is guided by the upper and lower flange portions 63 and 64, and the exhaust flow returns to the front side. May form. This exhaust flow becomes a flow that flows back to the exhaust outlet A, which leads to an increase in exhaust resistance. However, by providing the upper and lower regulation pieces 65 and 66 on the upper and lower flange portions 63 and 64, it is possible to regulate the exhaust flow that tends to separate from the guide surface 62 to the front side and guide the exhaust in the left-right direction. .. Therefore, by adopting the straightening vane 6A, the exhaust can be more satisfactorily guided toward both sides in the vehicle width direction.

(2) FIG. 15 is a cross-sectional view in the horizontal direction showing the main muffling device 2A according to the modified embodiment. The difference from the main muffling device 2 described above is that a support plate 33 that supports the exhaust introduction pipe 3 and the curved pipe 43 is adopted, and the support plate 33 further has an exhaust guide function. Since the other configurations are the same as those of the main silencer 2, the description thereof is omitted here.

The support plate 33 includes an integrally formed set plate portion 27A and an inner guide portion 34. The set plate portions 27A are provided in pairs on the left and right, and are portions that perform the same function as the set plate 27 that supports the curved pipe 43 in the above embodiment. The inner guide portion 34 extends in the left-right direction so as to connect the rear end edges of the pair of set plate portions 27A. The central portion of the inner guide portion 34 in the left-right direction has a convex curved surface protruding forward, and the central portion supports the downstream end 301 of the exhaust introduction pipe 3.

The inner guide portion 34 has a loose S-shaped curved surface on both the right side and the left side of the exhaust introduction pipe 3 in the top view. The S-shaped curved surface faces the right and left guide surfaces 62R and 62L of the straightening vane 6 at predetermined intervals to form an exhaust passage. That is, the exhaust gas discharged from the exhaust outlet A passes through the passage between the right and left guide surfaces 62R and 62L of the straightening vane 6 and the inner guide portion 34, and is satisfactorily guided in the left-right direction.

(3) In the above embodiment, an example is shown in which the first and second exhaust outlet pipes 4A and 4B include the first and second straight pipes 41 and 42 and the curved pipe 43. This is an example, and the first and second exhaust outlet pipes 4A and 4B may not include the curved pipe 43. Further, in the present embodiment, the curved pipe 43 that changes the exhaust path by 180 ° is illustrated, but it is sufficient if the exhaust path is curved in a U shape, and the curvature is slightly looser than 180 ° or slightly exceeds 180 °. Is also good.

1 Engine 10 Exhaust device 2, 2A Main silencer (exhaust silencer)
20 Silent body 203 Bead 21 Front wall 22 Houbi wall 23 Right wall (side wall)
24 Left wall (side wall)
25 Upper wall 26 Lower wall 27 Set plate 28 Mounting plate 3 Exhaust introduction pipe 4A 1st exhaust outlet pipe 4B 2nd exhaust outlet pipe 41 1st straight pipe 411 Upstream end 411 (other end)
412 Downstream end 412 (one end)
42 2nd straight pipe 43 Curved pipe 6, 6A Rectifier plate (exhaust guide)
61 Tip 62 Guide surface 63 Upper flange 64 Lower flange 65 Upper regulation piece 66 Lower regulation piece A Exhaust outlet B1 1st exhaust inlet B2 2nd exhaust inlet S Silent space St Streamlined part R Round part

Claims (10)

Exhaust silencer for vehicle engine
A silencer body that is partitioned by front and rear walls arranged in the front-rear direction of the vehicle, a pair of side walls arranged in the vehicle width direction, and upper and lower walls arranged in the vertical direction of the vehicle, and has a sound deadening space long in the vehicle width direction. When,
An exhaust introduction pipe that has an exhaust outlet and introduces the exhaust of the engine into the muffling space,
A first exhaust outlet pipe and a second exhaust outlet pipe, each having an exhaust inlet and discharging exhaust gas from the muffling space to the outside,
An exhaust guide unit for guiding the exhaust in a predetermined direction in the muffling space is provided.
The exhaust introduction pipe penetrates the front wall near the center in the vehicle width direction, and is arranged in the muffling space so that the exhaust outlet approaches the rear wall.
The first exhaust outlet pipe penetrates one of the side walls, the second exhaust outlet pipe penetrates the other side wall, and each of the exhaust inlets is in the vicinity of the front wall of the front wall. Arranged on one end side and the other end side in the vehicle width direction,
The exhaust guide unit is an engine exhaust muffling device that is arranged at a position facing the exhaust outlet and includes guide surfaces that guide exhaust from the exhaust outlet toward the rear wall toward both sides in the vehicle width direction. In the engine exhaust silencer according to claim 1,
The exhaust guide portion is arranged so as to face the central portion of the exhaust outlet in the vehicle width direction, and includes a tip portion extending in the vertical direction.
The guide surface is an engine exhaust muffling device having the tip end portion at the foremost portion and extending from the tip end portion toward the rear side of the vehicle on both sides in the vehicle width direction. In the engine exhaust silencer according to claim 2.
The exhaust guide portion is made of a plate-shaped member separate from the muffler main body.
An engine exhaust silencer in which an upper end side of the exhaust guide portion is attached to the upper wall of the silencer main body and a lower end side of the exhaust guide portion is attached to the lower wall. In the engine exhaust silencer according to claim 3,
The silencer body is an engine exhaust silencer having a streamlined shape on the rear side of the vehicle in a cross-sectional view in the vehicle front-rear direction in the central portion in the vehicle width direction. In the engine exhaust silencer according to claim 3 or 4.
The exhaust guide portion includes an upper flange portion extending forward from the upper end edge of the guide surface and a lower flange portion extending forward from the lower end edge of the guide surface.
An engine exhaust silencer having an upper flange portion attached to the upper wall of the silencer body and a lower flange portion attached to the lower wall of the silencer body. In the engine exhaust silencer according to claim 5,
The exhaust guide portion extends downward from the front end edge of the upper flange portion and partially covers the front of the guide surface, or extends upward from the front end edge of the lower flange portion and extends in front of the guide surface. An engine exhaust silencer with either or both of the partially covered lower control pieces. In the engine exhaust silencer according to claim 5,
The lower wall is provided with a bead extending in the front-rear direction of the vehicle.
The lower flange portion is an engine exhaust silencer that is attached to the lower wall via a mounting plate that straddles the bead and extends in the vehicle width direction. The engine exhaust silencer according to any one of claims 1 to 7.
An engine exhaust silencer having a rounded corner between the rear wall of the silencer body and the pair of side walls. The engine exhaust silencer according to any one of claims 1 to 8.
The first and second exhaust outlet pipes are a first straight pipe arranged so as to be adjacent to the front wall, a second straight pipe arranged substantially parallel to the first straight pipe, and a U-shape, respectively. A curved pipe curved in a shape is included, and one end of the first straight pipe and one end of the second straight pipe are connected to both ends of the curved pipe.
The exhaust inlet of the first and second exhaust outlet pipes is the other end of the first straight pipe, and is arranged so as to face the side wall, and the other end side of the second straight pipe has the side wall. The exhaust silencer of the engine that penetrates. In the engine exhaust silencer according to claim 9,
An engine exhaust silencer further comprising a set plate for supporting the curved pipe on the upper wall and the lower wall of the silencer body.

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